Terms for Batteries-Energy Density Definition:the amount of energy stored in a given system or region of space per unit volume or weight. Generally,with the same volume,lithium-ion batteries have an energy density that is 2.5 times of Ni-Cd batteries,and 1.8 times of Ni-MH batteries. 400 Li metal Li ion ('unsafe') 300 PLiON 200 洗 K6u3 Ni-Cd 100 Lead- acid Lighter weight 0 50 100 150 200 250 Energy density(W h kg) 66 • Definition: the amount of energy stored in a given system or region of space per unit volume or weight. • Generally, with the same volume, lithium-ion batteries have an energy density that is 2.5 times of Ni-Cd batteries, and 1.8 times of Ni-MH batteries. Terms for Batteries - Energy Density